A toner prepared by a typical mixing and kneading method (also referred to as a pulverization method) has been approaching the technical limit with regard to size reduction while involving problems such as an irregular form, a broad particle size distribution, and a high fixing energy. In particular, a releasing agent (wax) tends to exist on the surface of toner particles manufactured by a pulverization method because the toner particles tend to crack at the interface of the releasing agent. Therefore, such toner demonstrates good releasing effect but is not satisfactory about the performance because it easily attaches to carriers, an image bearing member and a blade. Thus, a method of manufacturing a toner by polymerization has been used to overcome such problems related to the toner manufactured by the mixing and kneading method. Toner is easily reduced in size according to this method and the particle size distribution thereof is relatively sharp in comparison with that of the pulverization toner. In addition, such polymerization toner can encapsulate wax. For example, unexamined published Japanese patent applications Nos. (hereinafter referred to as JOP) S63-282752 and H06-250439 describe technologies about the emulsification polymerization agglomeration method and JOPs 2000-275907 and 2001-305797 describe technologies for problems with regard to usage of a surface active agent in the emulsification polymerization agglomeration method. In addition, for example, JOP H11-133665 describes a dry toner having a substantial sphericity of from 0.90 to 1.00 which is formed by elongation reaction of urethane modified polyester functioning as a binder resin to improve the fluidity of toner, a low temperature fixing property, and hot offset resistance. Furthermore, for example, JOPs 2002-287400 and 2002-351143 describe a dry toner having a small particle diameter which has excellent powder fluidity, transferability, high temperature preservability, low temperature fixing property, and hot offset resistance. The methods of manufacturing toner described in these JOPs include a polymerizing process in which addition polymerization reaction is conducted between a polyester prepolymer having an isocyanate group and an amine in an organic solvent and an aqueous medium and a process of removing the organic solvent by heating. Particularly, JOP 2005 describes a method of removing the organic solvent in detail. In addition, for example, JOPs 2001-242663 and 2005-156586 describe a technology to obtain a sharp particle size distribution, and efficiently remove residual polymerizable monomers by controlling the liquid level during manufacturing of polymerization toner. However, in recent years, the market has been demanding reduction of the emission of carbon dioxide to relax the burden on the environment in addition to the further size reduction of the particle diameter to produce quality images, which leads to a strong demand for a further energy-saving machine. However, the low temperature fixing property and the high temperature preservation property are known to have a trade-off relationship.